Ill MOLLUSCA PARASITIC ON ECIilNODERMS 'J J 



where they probably subsist on the excreta, and are sometimes 

 found imbedded in the spines themselves. Bt. Turtoni occurs on 

 the British coasts on several species of Echinus, and Montacuta 

 suhstriata frequents Spatangus pvrpurcus and certain species of 

 Echinocardium, Cidaris, and Brissus. Lepton parasiticum has 

 been described from Kerguelen I. on a Hemiaster, and a new 

 genus, BoMllardla, has recently been established ^ for a Hyalinia- 

 shaped shell, parasitic on an Echinus from Mam^itius. (e) Holo- 

 thurioidea. The ' sea-cucumbers ' afford lodgment to a variety 

 of curious forms, some of which have experienced such modi- 

 fications that their generic position is by no means established. 

 Eiitoconcha occm-s fixed by its buccal end to the blood-vessels 

 of certain Synapta in the Mediterranean and the Philippines. 

 Entocolax has been dredged from 180 fath. in Behring's Straits, 

 attached by its head to certain anterior muscles of a Myriotro- 

 chusr' A curious case of parasitism is described by Voeltzkow ^ 

 as occurring on a Synciptct found between tide-marks on the I. of 

 Zanzibar. In the oesophagus of the Synapta was found a small 

 bivalve {Entovcdva), the animal of which was very large for its 

 shell, and almost entirely enveloped the valves by its mantle. 

 As many as five specimens occurred on a single Synapta. In 

 the gut of the same Holothurian lived a small univalve, not 

 creeping freely, but fixed to a portion of the stomach wall by a 

 very long proboscis which pierced through it into the body 

 cavity. This proboscis was nearly three times as long as the 

 animal, and the forward portion of it was set with sharp thorns, 

 no doubt in order to enable it to retain its hold and resist 

 evacuation. Various species of Eulima have been noticed in 

 every part of the world, from Norway to the Philippines, both 

 inside and outside Holothurians.^ Stilifer also occurs on this 

 section of Echinoderms.^ 



On Annelida. — Cochliolepas parasiticus has been noticed under 

 the scales of Acoetes lupina (a kind of ' sea-mouse ') in Charleston 

 Harbour.*" 



On Crustacea. — A mussel, ^ in. long, has been found '' living 



1 E. A. Smith, Ann. Mag. Nat. Hist. (6) iii. p. 270. 



- Journ. de Conch. (3) xxix. p. 101. ^ ^ool. Jakrh. AUh. f. Syst. v. p. 619. 



■* See especially Semper, Animal Life, Ed. 1, p. 3.51. 



5 Gould, 3Ioll. of U.S. expl. expcd. 1852, p. 207 {St. acicula, from Fiji). 



^ Stimpson, Proc. Bost. Soc. N. H. vi. ISf.S, p. 308. 



' Pidgeoii, 2\'aturc, xxxix. p. 127. 



