CRYPTOPHIALUS MINUTUS. 575 



always to be the case with the probosciformed penis); 

 and, lastly, they are lined by corimn, but are not occu- 

 pied by any vessel, gland, or organ of any kind. The only 

 function which I can assign to these appendages, is that of 

 aiding the retention of the ova within the sack : for the ova, 

 when first produced, are aggregated round them ; at this 

 period I several times observed long, somewhat curled, very 

 thin fibres, not tapering like hairs, adhering to both ap- 

 pendages, the nature of which fibres I cannot explain. In 

 very many cirripedes there seems a strong tendency to the 

 production of tapering, filamentary appendages, somewhat 

 like the two (*, 7c) here described, — namely, at the bottom of 

 the sack in some Balaninse, at the bases of the anterior cirri in 

 Lepas and in some other genera, and on the dorsal surface 

 of the prosoma in certain species of Pollicipes ; in this latter 

 case some of these appendages were covered by scales ; and 

 the prosoma whence they arose answers to the third seg- 

 ment of the body in Cryptophialus, or that supporting the 

 lower and larger appendage. Appendages of this nature, 

 in several cirripedes, serve for the lodgment of the testes, 

 but in some cases they are of no apparent use, excepting, 

 perhaps, in aiding respiration by the expansion of corium 

 thus exposed, and this partially may be their function here, 

 for there are no proper branchiae. 



Cirri. — There are three pairs, together forming a nearly 

 straight brush, of considerable length, projecting in a line 

 with the last thoracic segment. Each cirrus is biramous. 

 In a moderately large specimen there were twenty segments 

 in one of the longest rami. Each segment (fig. 14, a) is 

 strengthened by a dorsal or posterior shield of thickened 

 yellowish membrane, from the upper edge of which a single 

 smooth spine projects ; the anterior surface is likewise 

 strengthened on the two edges by thickened membrane, 

 and supports two pairs of long spines, which are plumose, 

 or rather hirsute, on both sides. In the lower segments 

 of both rami of the several cirri, the inner spine of each 

 pair is considerably shorter than the outer spine, — evidently 

 in relation to the little power of divergence of the two 

 rami. All the cirri resemble each other, excepting that the 

 rami of the anterior pair, are rather shorter than those 



