ADDITIONAL L.M.B.C. TUEBELLABIA. 175 



alternately by the two sides, the worm literally dragging 

 itself along "hand over hand." 



Verrill has suggested the generic name Heterostylochus 

 for this species, considering that by the possession of two 

 genital openings it has a right to generic distinction. 

 (Trans. Connecticut Acad., vol. viii., 1892, p. 467.) 



Family Leptoplanid^. 



Leptoplana tremellaris (0. F. Miiller). 

 Several specimens, under stones, at Port St. Mary and 

 Port Erin. 



B. COTYLEA. 



Family Euryleptid^e. 



Cycloporus papillosus, Lang, var. Icevigatus, Lang. 



Two specimens at Port St. Mary under the same stone 

 one of which measured 13*5 the other 11 mm. 



Two found by Prof. Herdman, adhering to a colony of 

 Botrylloides outside Port Erin Harbour, length 9 mm. 

 and 6 mm. respectively. I have not had sufficient exper- 

 ience of this species to say whether this marked difference 

 in size between the two individuals which usually consort 

 together is or is not constant ; further observations upon 

 this point will be of interest, as it is possible that these 

 couples which are so frequently found together represent 

 stages in which the male and female elements are respec- 

 tively at the maximum of development. 



The relation between Cycloporus and the Ascidians 

 with which it is so frequently associated is also a mystery, 

 whether Cyclopoi'us eats the Ascidian or merely derives 

 moisture from it during the period it is exposed by the 

 tide remains to be determined. 



Postcript : — Since the above was written I have found 



