410 THE OPISTHOBRANCHIATE 



Gill. — The gill of our specimens corresponds with Blochmann^s figure 

 of the gill of A. punctata, except that it is larger in our larger indi- 

 viduals. It is divided, of course, into a series of lamellae, but it 

 shows even in our largest specimens no trace of the bilobed appear- 

 ance figured by Blochmann for A. depilans. 



Mantle. — I have cut sections of the mantle of four specimens, large 

 and small, but cannot confirm Blochmann's statements as to the 

 presence of cilia over the upper surface. 



Breeding Habits. — I have only one fact to adduce under this head 

 as regards Plymouth specimens. An individual of a brown colour, 

 measuring nearly 4 inches when extended, was living in the 

 Laboratory for some time in the autumn of last year, and several 

 times deposited eggs in the form of slender gelatinous strings of a 

 brown-pink colour. 



Lo Bianco^ states that A. depilans spawns at Naples from March 

 to August, and A. punctata from April to August. A. limacina, 

 on the other hand, spawns all the year round, although especially in 

 the summer. 



Dr. Norman has observed Aplysia punctata spawning at Conne- 

 mara, and some of the shells of these individuals, according to Mr. 

 Hunt,^ measure only | inch in length. 



Mr. Hunt has also called my attention to a statement by Gwyn 

 Jeffreys, which is in itself a strong argument for the unity of the 

 two species punctata and depilans. In a Report on Dredging among 

 the Channel Islands,^ prepared for the British Association, Mr. 

 Jeffreys states, " It was also noteworthy that Aplysia depilans and 

 punctata (usually considered distinct species) copulated when a pair 

 was placed in a vessel of sea water. ^' 



Attitude. — I have often observed small Aplysise of about an inch 

 in length, when kept in a dish or aquarium, attach themselves firmly 

 by the posterior portion of the foot to the sides of the dish, extend 

 their bodies out at full length, and remain in this condition motionless 

 for hours together. As these small Aplysise have just the colour of 

 many red seaweeds among which they are generally dredged, I am 

 inclined to compare this habit with that of Geometer larvae, which 

 extend themselves also in a similar way, and are coloured like the 

 twigs upon which they are attached. These little Aplysise have a very 

 inanimate appearance in this condition, their tentacles and pleuro- 

 podia beingrendered prominent (the latter being generally compressed 

 or rolled together), and simulating the stunted branches of many 



' Notizie Biolog. rig. spec, il Periodo di maturita, ecc. Mitt. Zool. Stat. Neap., viii, 1888, 

 pp. 415, 416. 



= Loc. cit., 1878, p. 615. 



^ Rep. Biit. Assoc, vol. xxxv, Biriuingliani, 1865. 



