INVERTEBRATA, CRYPTOGAMIA, MICROSCOPY, ETC. 429 



granular nucleated masses ; they are open at the distal end. A nerve 

 enters proximally ; they arc probably olfactory. The sense of touch 

 seems to belong to the terminal hairs. The edge of the chelas, which 

 lies opposite to the " palm " of the joints on which they close, shows 

 small canals, entered proximally by a nerve and closed externally by 

 a knob, which j)robably convey tactile sensations. 



Hair-structures with Mechanical Functions. — In contrast to the above- 

 mentioned bail's, many, such as those on the feet, are used in swim- 

 ming, grasping, &c. The former function is discharged by the hairs 

 of the second pair of antenna) in those Caprellce in which these are 

 locomotor organs ; in this case the hairs are pilose and basal ly 

 jointed ; on the first maxillipede they are plumose. The feet carry 

 thorn-like points si)ecially adapted for holding prey. 



Circulatory System. — The elongated heart extends from the first 

 to the fourth segment, and is constricted between each two segments, 

 being almost cylindrical between the constrictions. The anterior 

 aorta divides, one branch jiasses between the halves of the chief 

 brain, the other passes back inferiorly to the stomach ; a posterior 

 aorta runs to the end of the fifth segment. The coi'puscles are 

 chiefly round in the arterial, fusiform in the venous blood. 



lie^jroductive Onjans. — These have been described fairly well by 

 Dohrn and Gamroth. The male generative opening is in front of 

 the base of the last maxillipede and lies in a small jointed process 

 which is present in many species, through which the vas deferens 

 passes. In the female the opening of the oviduct is guarded by a 

 muscular ring, — not chitinous, as Gamroth states. A rudimentary 

 third pair of lamina) for the retention of the ova is wrongly described 

 by Gamroth as a copulation-puuch. 



Digestive Organs. — Their structure agrees with that of other Am- 

 phipods in almost every point. The stomach is imperfectly divided 

 into an upper division for mastication, and a lower, paired, digestive 

 portion ; the chitinous capsule is prolonged forwards for some dis- 

 tance along the intestine on the inner side of its walls, as Dohrn has 

 described : the lateral plates and a downwardly projecting masticatory 

 process complete the chewing stomach-ai)paratus. The inferior — 

 digestive — division dilVers from that described for the Amphi2)oda in 

 being entered posteriorly by a pair of thin cliitin-lined ca,'ca ; tho 

 sides of the main sacs are lined by obliquely striated chitinous plates, 

 which present decided plications at the point nearest to the intestine, 

 and the cajca arc entered on each side by a bile duct, and it is jjcrhaps 

 here that tho food is mixed with the digestive fluids. In tho chitin 

 of the stomach two lamimc are distinguishable : tlic matrix, which 

 consists of polygonal nucleated cells, and tho cliitinous membrane 

 itself, which is thin, transparent, and gluss-like. The relation of tho 

 stomach to the intestine is remarkable ; a tumour-like protuberance 

 above tlie posterior end of the stomacli, is simply the fold formed by 

 tho invagination of the anterior end of the intestine into itself by the 

 stomach-tube (see above), and contains all tho ekinents of the intes- 

 tinal wall, exi-ept where it rests against tho stomacli, and here tho 

 muscular fibres are wanting. Tho paiivd tubes which lie at tho 

 posterior end of the intestine have been rightly described as urinary. 



