230 Miscellaneous. 



Remarkable Instances of Crustacean Parasitism. 

 By A. E. Verrill. 



In a collection of about ninety specimens of a small sea-urcliin 

 {Eury echinus imbecillis, Verrill) from the coast of Pern, not one 

 could be found in which the anal area and surrounding parts of the 

 upperside of the shell were not more or less irregularly distorted 

 or imperfect. An examination of the interior showed that in each 

 specimen a crab (Fabia chilensis, Dana), allied to the common 

 crab of the oyster {Pinnotheres ostrece), had effected a lodgment in 

 the upper part of the intestine, which had thereby been greatly dis- 

 tended in the form of a membranous cyst, attached to one side of 

 the shell, and extending aroimd to the lower surface near the 

 mouth. The shell is usually swollen on the side over the cyst ; and 

 the anal area is depressed and distorted, v/ith a large open orifice 

 {)assing obliquely into the cyst, out of which the crab may thrust 

 its legs at pleasure, but is apparently unable, when full-grown, to 

 come entirely out. All the specimens examined in the cyst were 

 females, carrying eggs ; but a very small crab found clinging among 

 the spines appears to be the male. The crab probably effects an 

 entrance into the intestine through the anus while quite young, and, 

 by its presence and growth in that position, causes the gradual dis- 

 tortion of the shell and formation of the cyst. In Prof. Dana's 

 Report on the Crustacea of the U. S. Expl. Expedition this crab is 

 described as from Valparaiso, from an Echinus; but no special notice 

 of its mode of occurrence and remarkable frequency appears to have 

 been published*. 



Another peculiar mode of parasitism I have observed in a sin- 

 gular crustacean (Hapalocarcinus marsiqiialis, Stimpsonf) from the 

 Sandwich Islands. This creature lodges itself among the slender 

 branches of a coral {Pocillipora ccssjntosa, Dana) and causes, pro- 

 bably by its incessant motions,the branches to grow up and surround 

 it on both sides by flat expansions of coral, terminating in digita- 

 tions which often interlock above, leaving openings between them 

 suitable for the uses of the parasite, but usually too small to allow of 

 egress. Most specimens of the corals of this species sustain one or 

 more, and often numerous, examples of these curious enlarged 

 bulbs among the branches. The habits were unknown to Dr. 

 Stimpson when he described his specimens, which had dropped 

 from among recently collected corals. — Silliman's Atnerican Journal, 

 July 1867. 



On the Anatomy q/* Balanoglossus (Delle Chiaje). 



By A. KOWALEWSKY. 



Under the name of Balanoglossus, Delle Chiaje described a vermi- 

 form animal of the Bay of Naples, known to the fishermen under the 

 name of lingua di bue. It has since scarcely attracted any attention 



* Pinnaxodis hirtipes, Heller, recently described from Ecuador and 

 found in an Echinus, is probably the same species, 

 t Proceedings Boston Soc. Nat. Hist. vi. 412. 



