64 



DOLABELLA.— AKERA. 



leaflets, are fixed upon the 

 back, by means of a broad 

 membranous pedicle, and 

 covered by a small mantle 

 (m), in the thickness of 

 which we find a small 

 horny shell. And the anus 

 is situate behind the bran- 

 chiae. These moUusks live 

 on fiicus, and are provided 

 with an enormous crop, 

 and three other stomachs 

 {fig. 82, d), the second 

 and third of which are arm- 

 ed internally with sharp 

 hooks, and cartilaginous 

 plates. A particular gland 

 secretes an acrid liquor, and 

 pours it out through an 

 opening situate on the right 

 side. A purple coloured 

 liquid exudes sweats 

 from the edge of the 

 mantle, when the animal 

 contracts, and is sufficient 

 in quantity to dye the 

 water to a considerable distance around it. Several species 

 of Aplysice, which vary in colour, are found on the coasts 

 of France. 



39. The DolahellcB do not differ much from the Aplysise, 

 except in the position of their branchiae, and their mantle at the 

 posterior extremity of the body. They are found in the Medi- 

 terranean as well as in the Indian seas. 



40. The AkercB {fig- 83) also resemble the Aplysise in the 

 complication and armature of the stomach, as well as in the posi- 

 tion of their branchiae, and several other important points of their 

 organization ; but they are distinguished by their tentacles, which 

 are short, very thick, and so arranged as to form together a 



Fig. 82. AFLYSTA. 



Explanation of Fig. 82. — Anatomy of the Aplysia : — a. the head ; — h. the 

 pharynx ; — e. ccsopliagus ; — d. the three stomachs ; — c. the intestines ; — -/. 

 the nervous collar surrounding the CESopliag-us ; — g. the heart; — h. the 

 branchia; ; — i. the liver ; — •_;". the anus ; — k. the bladder : — I. the ovary. 



39. What is Dolabe'lla? (Dolabella, Latin, a little axe or hatchet.) 



40. How are Ake'rae distinguished from the Aplysiae ? (Akera, from the 

 Greek, c, without, and keras^ horn.) 



