40 Mr. J. 1). Macdonald on a Bitentaculate Slug 



uterus, is so short, that the sac itself Ues in contact with that 

 tube. Now, in the common Slugs of England, the duct of the 

 spermatheca has no immediate communication with the oviduct, 

 but opens externally by a distinct orifice in the generative pit. 



Near the commencement of the uterus there is a much smaller 

 sac-like appendage (w), which may be a rudiment of the mul- 

 tifid vesicles; organs which, although peculiar to the genus 

 Helix, I have never seen in any of the numerous Helices which 

 I have dissected in the Southern hemisphere. 



The external respiratory opening leads into a small cavity 

 with stout areolated walls, and a few little fenestrations in a 

 small cribriform space establish a communication between this 

 cavity and the pericardium -, a condition which also most di- 

 stinctly exists in Nautilus Pompilius. 



The heart (r) holds a central position ; a small auricle receives 

 the return-blood from the respiratory surface on the right side, 

 and the ventricle gives oif its principal arterial trunk inferiorly, 

 a tubular process of the pericardium encircling the vessel at its 

 origin. 



A large glandular body (s) arches over the viscera from the 

 left to the right side immediately behind the heart, and pours 

 forth its mucous secretion through the respiratory orifice. This 

 gland is furnished with compressor muscles from the circular 

 fasciculi of the integument. It is doubtless the homologue of 

 what might be termed the renal gland of Paludina for example, 

 or the renal follicles of Nautilus \ and indeed the close rela- 

 tionship of the Gasteropoda with the Cephalopoda through the 

 latter genus is well illustrated in many particulars in the little 

 mollusk, the principal details of whose anatomy have just been 

 given*. 



The only mollusk with which this may be confounded is the 

 Janella antipodarum of Dr. Gray. The primd-facie probability 

 of their identity was first suggested to me by Mr. Macgillivray 

 in the following memorandum, which expresses the state of the 

 question so concisely that I cannot refrain from inserting it, 

 with that gentleman^s permission : — 



" Limax bitentaculatus, Quoy & Gaim. Voy. Astrolabe, t. 13. 

 f. 1, 2, 3. From this description Gray formed a temporary genus 

 under the name of Janella, in vol. iv. of ^ Mrs. Gray^s Mollusca.^ 

 He has since, from receiving one in spirits, published the cha- 

 racters of the genus (in Ann. and Mag. of Nat. Hist, for Dec. 



* I have since ascertained that a bitentaculate Slug, answering in every 

 respect to that above described, is indigenous to Port Ste[)hens, New South • 

 Wales. Both unquestionably belong to the same genus, but not having 

 the o])portunit3 of conii)aring specimens, I cannot determine if any specific 

 differences exist between them. 



