INVERTEBRATA, CRYPTOGAMIA, MICROSCOPY, ETC. 769 



of the " aquiferous system " appears to lie a little above the genital 

 orifice ; the heart has its long axis set transversely to that of the body, 

 and the ventricle is, in position, a little superior to the auricle ; the 

 aorta is a vessel of some size which bifurcates at a very short distance 

 from the heart into an anterior and a posterior aorta. These and 

 their branches have their course described in some detail ; but, in con- 

 sequence of the rarity and small size of these creatures, the author 

 is not able to make this chapter as complete as he could wish. 



Reproductive Organs. — Hermaphroditism appears to be especially 

 complete in Gasteropteron, for there is only a single duct for the pur 

 pose of carrying away the male and female products. But our spaco 

 does not permit us following the author through his important account 

 of the details. 



Nervous System. — The oesoiDhageal collar is formed by three pairs 

 of ganglia, connected together by commissures of different lengths ; 

 all these — cerebral, pedal, and visceral — are placed more or less to the 

 sides of the collar, but the first have, of course, a more distinctly 

 dorsal position. Among the protecting parts we may note a mass of 

 hyaline cells which ajjjDear to be in relation to the integument ; re- 

 calling by their character hypodermic glands, they seem to discharge 

 a more or less mucilaginous fluid which aids in lessening any shocks 

 to the nervous centres. 



After giving a detailed description of these ganglia and of the 

 nerves which pass off from them, the author turns to the stomato- 

 gastric and to the genital ganglia ; the sense-organs are next dealt 

 with, and here we have to note that, although the dorsal tentacles are 

 in all Bullidea completely wanting, and are partially replaced by the 

 cephalic disk, this last-mentioned organ must not be considered 

 merely as an atrophied tactile organ, for the olfactory sense, which is 

 ordinarily exercised by the extremity of the tentacles, has its seat in 

 a more or less well-marked differentiation of that portion of the integu- 

 ment which lies between the cephalic disk and the foot ; in Gasterop- 

 teron this sense seems to be completely absent, but the tactile organs 

 are, as comi)ared with the allied forms, very richly developed. After 

 a description of the optic and auditory organs, the author passes to 



Tlie Anatomy of some Allied Genera {Doridium,Philine, Scaphander, 

 and Bulla) ; of this the following is a very brief abstract. — The most 

 striking point in Doridimn is the structure of its copulatory organ ; in 

 this genus the penis does not, as in most Molliisca, form a thick- walled 

 tube, but a canal not completely closed, for four-fifths of its length 

 the left edge of the canal lies over the right, but at its superior 

 cxtronity there is a kind of groove, which is so formed that the orifice 

 of the duct is not terminal, but ventral in position. 



In Philine and Scaphander the salivary glands are very short and 

 cylindrical, instead of being elongated as they aic in most members of 

 this family ; there are only two hepatic orifices, and the circumoral 

 glands are feebly developed. The olfactory and optic organs aro 

 exceedingly rudimentary ; the jicnis of Philine is hammer-shaped, 

 while in Scaphander this organ is completely absent. 



As to classification, M. Vnyssi^re docs not find himself in agrcc- 



VOIi. III. 3 E 



