524 PYCNOGONIDA CHAP. 



doubt that they contained the remains of larvae of a Pycnogonid, 

 so that the deep-sea Pycnogonids, which are so abundant, very 

 possibly pass through their early stages in deep-sea Stylasteridae. 

 . . . The gastrozoids containing the larvae were partly aborted." 



A Pycnogon larva, doubtfully ascribed to Nymphon, has been 

 found living in abundance ectoparasitically on Tethys in the Bay 

 of Naples. 1 



Habits. Of the intimate habits of the Pycnogons we can 

 say little. Pycnogonum we often find clinging, as has been said, 

 close appressed to some large Anemone (Tealia, Bolocera, etc.), 

 whose living juices it very probably imbibes. The more slender 

 species we find climbing over sea- weeds and Zoophytes, where 

 sometimes similarity of colour as well as delicacy of form helps 

 to conceal them ; thus Phoxichilidium femoratum (Orithyia 

 coccinea, Johnston) is red like the Corallines among which we 

 often find it, P. virescens green like the filamentous Ulvae, the 

 Nymphons yellowish like the Hydrallmania and other Zoophytes 

 which they affect. On the New England coast, according to Cole, 

 the dark purple Anoplodactylus lentus, Wilson (Phoxichilidium 

 maxillare, Stimpson), is especially abundant on colonies of 

 Eudendrium, whose colour matches its own, the yellowish Tany- 

 stylum orbiculare frequents a certain yellowish Hydroid, and of 

 these two species neither is ever found on the Hydroid affected 

 by the other ; while, on the other hand, Pallene brevirostris, whose 

 whitish, almost transparent body is difficult to see, is more 

 generally distributed. 2 The deep-sea Pycnogons (Colossendeis, 

 Nymphon) are generally (if not universally) of a deep orange- 

 scarlet colour, a common dress of many deep-sea Crustacea. 



The movements of the Pycnogons are singularly slow and 

 deliberate ; they are manifestly not adapted to capture or to kill 

 a living prey. Linnaeus accepted from J. C. Konig the singular 

 statement that they enter and feed upon bivalve shells, " Myti- 

 lorum testes penetrat et exhaurit"; but the statement has never 

 been reaffirmed. 3 



1 Hugo Mertens, Mitth. Zool. Stat. Neapel, xviii., 1906, pp. 136-141. 



- One is tempted to explain such cases as the above of harmonious or identical 

 coloration by the simple passage of pigments unchanged from the food. 



3 Fabricius says of his Pycnogonum (Nymphon) grossijws, " Vescitur insectis et 

 vermibus marinis minutis ; quod autem testas mytilorum exhauriat mihi ignotum 

 est, dnm nunquam intra testam my till illud inveni, licet sit verisimile satin," 

 Fauna G'rocnlaadica, p. 231. 



