IV ACROTIIORACICA — ASCOTHORACICA 93 



distinguished from all the foregoing Cirripedes by the presence 

 of a well -developed abdomen. Since the discovery of other 

 allied genera, it has been decided that the abdomen is equally 

 reduced in these forms, and that the terminal ap])endages do not 

 belon" to this retJ-ion, but to the thorax. 



The sexes are separate. The body of the female (Fig. 64, A) 

 is enclosed in a chitinous mantle, armed with teeth by which 

 the excavation is effected, and is attached to the cavity in the 

 liost by means of a horny disc. Upon this disc the dwarf 

 males (B) are found. 



Alcij)2)e lampas inhabits holes on the inner surface of dead 

 Fusus and Bitccinum shells; CryiJtoplnalns minutvs the shells 

 of Condi ole-pas -peruviana ; C. striatus ^ the plates of Chiton ; 

 Kochlorine hamata the shells of Haliotis; and Lithoglyptes 

 varians shells and corals from the Indian Ocean. 



Sub-Order 4. Ascothoracica. 



These are small hermaphrodite animals completely enveloped 

 in a soft mantle, which live attached to and partly buried in 

 various organisms, such as the branching Black Corals (Gcrardia). 

 They retain the thoracic appendages in a modified state, and the 

 l)ody is segmented into a number of somites, the last of which 

 probably represents an abdomen. 



Laura gerardiae, described by Lacaze Duthiers," is parasitic 

 ^)\i the stem of the "Black Coral," Gcrardia (vol. i. p. 40 6); it 

 has the shape of a broad bean, the l)ody being entirely enclosed in 

 a soft mantle, with the orifice in the position corresponding to 

 the hilum of a bean. The body lying in the mantle is composed 

 of eleven segments, and is curved into an S-shape. Its internal 

 anatomy is entirely on the plan of an ordinary Cirripede. 



Petrarca liatJiyactidis, G. H. Fowler,^ was found in the 

 mesenteric chambers of the coral Bathyactis, dredged by the 

 Challenger from 4000 metres. The body is nearly spherical, 

 and the mantle-opening forms a long slit on the ventral surface. 

 The mantle is soft, but is furnished on the ventral surface with 

 short spines. 



The antennae, which form the organs of fixation, remain 



1 Bunidt, Sitzh. Ges. Naturfr. Berlin, 1903, p. 436. 



- Arcli. Zool. Exp. viii., 1880, p. 537. 



3 Quart. J. Micr. Set. xxx., 1890, p. 107. 



