740 



Stylops ist die paläarktische und die nearktisclie Region, doch habe ich 

 von Nordamerika nur einige wenige Exemplare einsehen können. 

 Schwerin, i, M. den 20. Januar 1906. 



5. Feeding habits of the Pycnogonid Anoplodactylus lentus. 



By Leon J. Cole. 



eingeg. 23. Januar 1906. 



It has always been assumed that pycnogonids live by sucking the 

 juices of the hydroids, tunicates, and similar animals with which they 

 are commonly found associated. The proboscis appears to be developed 

 essentially as a sucking organ, and its shape is such as to suggest, in 

 many cases, that it can be inserted through the outer tissues of the 

 bodies of these other invertebrates, its hosts, to secure the more fluid 

 portions within. This apparent adaptation is carried to the extreme in 

 Pipetta iveberi^ recently described by L ornane Very few direct obser- 

 vations on the feeding habits have been made, however, and so far as I 

 am aware, all that have been recorded refer to the larvae. 



Hall ez 2 has recently given an excellent resumé of the knowledge 

 concerning the parasitism of pycnogonid larvae in the gastral cavity of 

 hydroids, adding observations of his own on the occurrence of larvae of 

 Phoxichilidium (probably femoratum) in Bongainrillia. In Anoplodac- 

 tylus {=^Phoxickilidium) plumidariae von Lendenfeld-' found that the 

 larvae attach themselves to the outside of the hydroid by means of their 

 large checifori, and insert the proboscis directly into the tissues of the 

 host, as it is commonly supposed the adults of most species do. 



In a previous paper* I pointed out one very important obvious 

 function of the chelifori in larval Pycnogonida, viz., that they serve the 

 young for attachment, thus preventing their being swept away by tides 

 and currents, until the claws of the legs have become developed enough 

 to be functional. I suggested further that in such forms as Anoplodac- 

 tylus and Phoxichilidium^ in which the chelae are retained by the adult, 

 and are in intimate relation with the mouth, that they would be found to 

 subserve some purpose in connection with feeding. And such, in fact, 

 I have now observed to be the case. 



1 Loman, J. C. C, Pipetta weberi n. g.. et n. sp., with notes about the probos- 

 cis of the Pycnogonida. Tijdschr. d. Ned. Dierk. A^ereen. ;2) Vol. 8. p. 259—266. 1904. 



2 Hallez. Paul, Observations sur le parasitisme des larves àes Phoxichilidium 

 chez Bougainvillia. Arch. d. Zool. Expér. (4) Vol. 3. p. 133—144, pi. 6. 1905. 



3 von Lendenfeld, E.., Die Larvenentwicklung von Phoxichilidiìim phimu- 

 lariae nov. sp. Zeitschr. f. wiss. Zool. Vol. 38. p. 323—329. 1883. 



4 Cole, Leon J., Pycnogonida collected at Bermuda in the summer of 1903. 

 Proc. Bost. Soc. Nat. Hist. Vol. 31. p. 316. 1904. 



