150 PKOCEEDINGS OF THE MALACOLOGICAL SOCIETY. 



if eitter be intended it is not tlie former : this is of interest -with, 

 reference to Humbert's genus. 



The shell of a specimen from the same locality was afterwards figured 

 by Fischer in 1856/ and placed in the genus Viquesnelia, Deshayes 

 (created for a fossil shell), under Valenciennes' manuscript name. 



Humbert^ next, in 1862, described a new genus Tennentia to contain 

 a Cingalese slug T. Thivaitesii, practically identical with the first 

 mentioned, on the strength of the fact that the mantle was "entire, 

 not fringed." The description is much fuller than Gray's, being 

 accompanied by figures of animal, shell, jaw, and radula, but the 

 only further point of historical interest is the statement that the 

 respiratory opening is in a notch ' ' in the middle of the right side 

 of the mantle." 



The Vega Expedition brought home from Ceylon a slug which 

 "Westerlund^ in 1887 differentiated under the name of Vega JSforden- 

 skioldi. The old fallacy about the " fringed mantle " again prevented 

 the form described from being placed in Marimlla ; an additional 

 reason for separating the new form from the latter being the absence 

 of a fleshy 'collar.' From Humbert's Tennentia the Vega's slug 

 differed, it was supposed, in having the respiratory orifice not in the 

 middle, but anteriorly placed on the right side of the mantle. An 

 examination of the figure brings out the fact that the free portion 

 of the mantle which forms the collar is shown, but that it, as well 

 as the head, is contracted, and hence it follows that the position of the 

 respiratory opening must necessarily lie nearer to the anterior end of 

 the body and mantle than when the slug is more extended. 



The other differences between Vega and Tennentia are based 

 apparently upon Semper' s'' description of Tennentia Philippinensis, 

 but since the anatomy of that animal differs very markedly from 

 Maricella, in the spermatheca being sessile (showing a relationship 

 to Parmarion) and in the central tooth of the radula being absolutely 

 unlike that of the former genus, the arguments based upon it can 

 have no weight in the present discussion. 



In 1888 Godwin-Austen^ made a new subgenus of Girasia, Gray 

 (= ITelicarion), to wit, Belchania, afterwards raised to generic rank,^ 

 to contain a form {D. Beddomei) shown to be generically identical 

 with Maricella by its external characters, jaw, and radula. 



A brief description is given and allusions made for the first time 

 to the anatomy of the soft parts, the genitalia being described as 

 "like those of Girasia save that the amatorial organ (dart sac) is 

 not so large." The anatomy of the latter genus was previously 

 described by Godwin-Austen,' therefore no detailed account is given 



Journ. de Couch., 1856, p. 290, pi. vii, fig. 18. 



Rev. & Mag. Zool., 1862, p. 428, pi. xvii, fig. 1. 



Vega Exped., vol. iv (1887), p. 188, pi. ii, figs, la & \h. 



Reisen Archipel Pliilippinen, yoI. ii (1870), pt. iii, p. 7. 



Land and Fresh-water Mollusca of India, p. 242, pi. Iviii. 



Op. cit., p. 253. 



Proc. Zool. Soc, 1880, p. 293, pis. xxiv, xxv. 



