"Ventral aspect of femal shore crab. Abd., Abdomen; mxp., third maxillipede." -Thomson, 1916
"Acorn-shell (Balanus tintinnabulum). T., tergum; CR., thoracic legs; R., outer shell in section; D.,…
"Nebalia. SH., Shell; A.1, first antennae; A.2, second antennae; TH., 8 thoracic limbs; Ab.4, Ab.6,…
"Hermit-crab withdrawn from its shell. The anterior appendages are broken off. hd., Head; th., thorax;…
"Dissection of Peripatus. at., Antennae; or.p., oral papillae; c.g., cerebral ganglia; sl.d., duct of…
"Ventral aspect of male cockroach with the wings extended. An imaginary median line has been inserted.…
"Leg of cockroach. c., Broad expanded coxa; tr., trochanter; f., femur; ti., tibia; ta., six-jointed…
"Transverse section of insect. h., Heart; g., gut; n., nerve-cord; st., stigma; tr., trachea; w., wing;…
"Head and mouth parts of bee. a., Antenna; m., mandible; g., labrum or epipharynx; mx.p., rudiment of…
"Mouth-parts of mosquito. a., Antennae; lxe., labrum and epipharynx; mn., mandibles; hp., hypopharynx;…
"A transverse section before the union of the amnion folds, and a longitudinal median section after…
"Acerentomon, a very primitive insect. H, Head; TH.1, TH.2, TH.3, terga of thoracic segments; 1, 2,…
"Vertical cross-section of a Trilobite (Calymene). i., Intestine; s., shield; L., endopodite; e., exopodite;…
"Male of Nymphon. PR., Proboscis; CH., chelophores; P., pedipalps; E., eggs carried on ovigerous legs;…
"Ideal mollusc. m., Mouth; g.c., cerebral ganglia; c., edges of mantle skirt; z.g., duct of right lobe…
"Roman snail (Helix pomatia). Note shell covering visceral hump; p.ap., pulmonary aperture (including…
"Vertical section of the shell of a species of Helix. M., Mouth of shell; A., apex; C., columella."…
"Dissection of snail. T., Short horn; TT., long horn with eye; N., cerebral ganglia; S.G., salivary…
"The fresh-water mussel...the bivalve in motion in the mud with protruded foot (F.); nonte inhaland…
"The fresh-water mussel...the inside of the shell (left valve)...u., The umbo; L., the ligament; c.t.,…
"The fresh-water mussel...the outside of the shell (right valve)...u., The umbo; L., the ligament; l.g.,…
"Diagram of the structure of Sepia. a., Eight short arms around mouth; l.a., one of the two long arms;…
"Diagram of circulatory and excretory systems in a Decapod-like Sepia. 1, Gill; 2, renal sac; 3, afferent…
"'Nurse' of Doliolum mulleri. I., Inhalant, E., exhalant aperture; C., ciliated band round pharynx (P.);…
"Sexual individual of Doliolum mulleri. G., gonads; B., gill-slits; I., Inhalant, E., exhalant aperture;…
"Diagram of Salpa africana. o.a., Oral aperture; d.t., dorsal tubercle; te., tentacle; g., ganglion;…
"Lateral view of Amphioxus. The notochord runs from tip to tip. t., Tentacular cirri; G., reproductive…
"Partial section of a Vertebrate brain (diagrammatic). OLF., Olfactory lobe; CH., cerebral hemispheres;…
"Diagrammatic section of spinal cord. p.f., Posterior fissure; p.c., posterior column of white matter;…
"Diagram showing the ear and related parts in a young cat. P., Pinna; Sq., squamosal: E.A.M., external…
"Diagram of the eye. C., Cornea; a.h., aqueous humour; c.b., ciliary body; l., lens; I., iris; Sc.,…
"Section through a young newt. c.t., Connective tissue; E., epidermis; D., dermis; S.C., spinal cord;…
"Median longitudinal section of anterior region of Myxine. B., Barbule; N., nasal aperture; NT., nasal…
"Respiratory system of hag, from ventral surface. b., Barbules; m., mouth opening on ventral surface;…
"Bdellostoma stouti (Californian hag), enveloped in sheath of mucus. b., barbules e., eyes m. mucus;…
"The lamprey (Petromyzon marinus). I. Then entire animal; note the seven gill-slits of which the first…
"Under surface of skull and arches of skate. l.1, First labial cartilage; R., rostrum; tr., trabecular…
"Side view of skate's skull. l1., First labial cartilage; n.c., nasal capsule; a.o., antorbital; p.pt.q.,…
Skeleton of skate. nc, nasal capsules; pq, palato-pterygo-quadrate cartilage; M, Meckel's cartilage;…
"Dissection of nerves of skate. CH., Cerebral hemispheres; O.TH., optic thalami; OL., optic lobes; M.,…
"Heart and adjacent vessels of skate. v., Ventricle; c.a., conus arteriosus; p.i., posterior innominate;…
"The haddock. n.a., Nasal apertures (double on each side); d.f.1, d.f.2, d.f.3, dorsal unpaired fins;…
"External characters of a Teleostean--a carp (Cyprinus carpio). R., Dorsal unpaired fin; S., homocercal…
"Section of a Teleostean gill. G.F., Gill-filament; A., artery (venous blood); V., vein (pure blood);…
"Diagram of Teleostean circulation. A., auricle; V., ventricle; v.a., ventral aorta; a.br., afferent…
"Young skate. The yolk-sac has been cut off, the yolk-stalk is left. m., Mouth; ol.o., nostril, e.g.…
"Lateral view of dogfish (Scyllium catulus). Note ventral mouth with naso-buccal groove, heterocercal…
"Outline of Acanthodes sulcatus. p., Pectoral fins; v., pelvis; a., anal; d., dorsal." -Thomson, 1916
"Larva of Polypterus. e.g., Large external gill of the hyoid arch; Pc., pectoral fins; Pv., pelvic fins.…
"Lepidosiren showing (Pc.f.) pectoral fin and the tufted pelvic fin (Pv.f.) of the mature male." -Thomson,…
"Skeleton of Ceratodus fin. a., Central axis; r., radials; h., basal piece." -Thomson, 1916
"Head region of Protopterus. sn.t., Sensory tubes; l.l., lateral line; e.br., external gills; pc.l.,…
"Larva of Protopterus. e.g., external gills; Pc., pectoral fin; Pv., pelvic fin." -Thomson, 1916
"Skull of frog. Upper surface-- Pmx., premaxilla; N., nasal; M., maxilla; Sq., squamosal; Q.j., quadrato-jugal;…
"Skull of frog. Lower surface-- Pmx., premaxilla; M., maxilla; Q.j., quadrato-jugal; Q., quadrate; Pt.,…
"Skeleton of frog. The half of the pectoral girdle, and fore- and hind-limb of the right side are not…
"Pectoral girdle of Rana esculenta. The cartilaginous parts are dotted. Ep., Episternum; om., omosternum;…
"Nervous system of frog. 1-10, The cranial nerves; oc., eyes; crb., in front of optic chiasma; to.,…
"Longitudinal vertical section of frog embryo, shortly before closure of blastopore. FB., fore-brain;…