THE ANATOMY OF A NEW SPECIES OF I'.ATII VDORIS. 281 



There is no second sac on the course of the vagina, which is also the only connection 

 between the buisa and the female channel. From this it follows that the herma- 

 phrodite duct of Bathydoris divides but once namely, into a male and a female duct. 

 The Dorid duct bearing the so-called spermatoryst, and connecting the bursa with the 

 region of fertilisation in the course of the ovidue.1, is totally unrepresented. In short, 

 Bathydoris In-mniii is typically diuulic, like Ti-it'mi and the Pleurobranchids. 



Externally, the everted organs are surrounded by a rim representing the limit of 

 the common genital vestibule of the male and female system. 



SYNOPSIS OF SPECIFIC AND GENERIC CHARACTERS. 



When we come to analyse the differences between the foregoing account and those 

 of the two previous investigators of the genus, we encounter considerable difficulties in 

 deciding which are specific differences and which may be put forward as corrections. 

 To the latter category we may presume to relegate all differences in regard to which 

 previous statements have been qualified or made with reservation. 



The specific distinctness of Bathydoris liroirnii is undoubtedly more striking than 

 that of any of the other recorded species, and, since the animal was mature, there can 

 be no question of its being the young of any one of them. Among characters pre- 

 sumably not of generic rank which distinguish the species may he mentioned the 

 following : 



1 I ) The uniformity in size and shape of the lateral teeth of the radula. 



(2) The pitted pad on the glans penis. 



(3) The immediate sinistral bend of the oesophagus at its origin from the buccal 



mass and the unequal lengths of the cerebro-buccal connectives. The 

 causal connection between these two features stamps them as true anatomical 

 constants. 



(4) The two tufted gills placed on a traverse ridge symmetrically in front of the 



anus. 



On the basis adopted above, it is likely that the following features in which the present 

 account differs from those of BERGH and ELIOT may be regarded as of generic value : 



(1) The diauly of the reproductive system. 



(2) The circular canal embracing the pericardium and collecting blood from the 



dorsal integument. 



(3) The foilicular nature and great size of the salivary glands. 



(4) The presence of two blood glands on the wall of the kidney (the structures 



described as such by BKUCH and ELIOT turned out, on histological examina- 

 tion, to be the follicles of the salivarv glands ; the true blood glands were 

 not seen by these authors). 



(5) The asymmetrical opening of the efferent vein into the auricle. 

 ((>) The great saccular kidney with its ventral wall thrown into folds. 



(ROY. soc. EDIN. TRANS., VOL. L., 203.) 



