BEACHYUKA FROM TOREES STEAITS. 45 



So far as I can discover, no furtlier description of this remarkable form has been 

 published. Semper gives a figure of it, but it is on too small a scale to be of much use. 

 It represents the carapace as proportionately broader than in our specimens. All the 

 recorded specimens have been females. 



The peculiar habitat of this Crab was unknown to Dr. Stimpson, who states that his 

 specimens were found " clinging to the branches of living madrepores at the depth of 

 one fathom in the harbour of Hilo, Hawaii." 



Ehrenberg had long before noticed certain deformities on corals caused by the presence 

 of Crustacea, and had compared them to the galls formed by plants. In his work on the 

 Corals of the Red Sea he writes of the species Serlalopora subidatn, Lamk. : — 

 " Paguri parvi (P. comlUophilos) domicilia in ramis efiiorescentibus sibi pcirant, et veras 

 gallas fere eliciunt, quales plantse gerunt" (Beitr. z. Kennt. Korall. roth. Meeres, p. 123). 

 I am not aware that Ehrenberg's " Payurus " has since been recognized, or that any other 

 Pagurid has been found inhabiting coral-galls, so that it is possible that Ehrenberg's 

 remarks may really refer to the present species *. Be this as it may, Verrili was the first 

 to definitely associate these coral-" galls " with Stimpson's Rapalocannnus. In a paper 

 on "llemarkable Instances of Crustacean Parasitism " (Amer. Journ. Sci. (2) xliv. 1867, 

 p. 120) he writes : — " Another peculiar mode of parasitism I have observed in a singular 

 ernstacean {Kapalocarcinus marsupialls, Stimpsou) from the Sandwicli Islands. This 

 creature lodges itself among the slender branches (jf a coral [PociUopora cccspltosa, 

 Dana), and causes, probably by its incessant motions, the branches to grow up and 

 snrround it on both sides by fiat expansions of coral terminating in digitations which 

 often interlock above, leaving ojienings between them suitable for the uses of tlie 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." In a subsequent paper " On the Parasitic Habits of Crustacea " (Amer. 

 Nat. iii. 1869, p. 239), Prof. Verrili adds that he had " observed similar cavities on 

 Pocillopjora elonguta from Ceylon, which are probably made by another species of the 

 same genus." In his " Synopsis of the Polyps and Corals of the North Pacific Exploring 

 Exi^edition " (Proc. Essex Inst. vi. (1S68) 1870, p. 91), the same writer records the 

 occurrence of galls on most of the sjoecimens of Pocillopora ccespitosa, Dana, from the 

 Hawaiian Islands, and he also writes of P. brecicoruis, Lamk. : — " One specimen has a 

 bulb similar to those made by Hapalocarcinus marsiiphdis, l)ut belonging prol)ai)ly to 

 another species of the same genus, since it differs con.siderably in form. The aperture is 

 closed except a few small openings above." 



In the general account of his researches in the Philippine Islands (Zeit. wiss. Zool. xiii. 

 1863, p. 560), Semper has a note on a small " Porcellana " which he found living iu 

 cavities in a " millepore." In his work on ' The Natural Conditions of Existence as 



* I leani from Mr. R. Kiikpatrick, who has been kind enough to find the above quotation forme, that Kluuzinger 

 refers to Ehrenberg's observations, and gives a figure of the galls on the same sjjecies of coral (which he refers 

 to -S'. siiiiiosa, M.-E. &. H.) without, however, giving any details as to the parasite (Korall. rjlh. iloer. ii. p. 72, 

 pi. vii. fig. 15). 



