St. Andreios Marine Laboratory. 101 



of coenosarc, with a more or less perfect coating of chitin, 

 terminating in a polypite with two or four tentacles, and pro- 

 vided with the elongated oral tube, which was bent round, 

 apparently in quest of prey, and often dilated at the extremity. 

 Secondary buds, possessing only two tentacles, and thus 

 somewhat approaching the peculiar Lar sahellarum in appear- 

 ance, occurred at intervals in the course of the former. The 

 coenosarc connected with these young buds entered portions of 

 the tubes forming the old polyparyj and sometimes terminated 

 abruptly in a bulbous mass, in the interior of which the cilia 

 were specially active. Dujardin states that the species feeds 

 especially on Cyclops and other minute Crustacea. If the 

 polypites inhabiting these older sheaths had died on the escape 

 of the free zooids, or from causes connected with their arti- 

 ficial life, the vitality of the coenosarc had enabled the species 

 again to make rapid progress by gemmation. 



3. On the Commensalistic Habits of the Larval 

 Forms o/'Peachia. 



Considerable information has recently been obtained con- 

 cerning the history of larval Actinise commensalistic on 

 Medusse both in our own and foreign seas. Much of this 

 has been collected by Prof. Haddon in his very interesting 

 account of the parasitic larva of Ilalcampa *, which he found 

 for the most part attached to the stomach on the sub-umbrella 

 of different species of Leptomedusa. Before the publication 

 of the latter paper, however, the occurrence of considerable 

 numbers attached to various kinds of Thaumantias in St. 

 Andrews Bay had led me to think that this must be a very 

 general habit of these larval forms, which I associated with 

 the commonest type here, viz. Peachia hastata, Gosse, first 

 recognized as a British species by the late Prof. John Reid, 

 of St. Andrews, under the name of Actinia cylindrica\. 

 They occurred in various parts of the bay, though the greatest 

 number were procured by a single sweep of the mid-water net 

 off the mouth of the Eden. They cling to various parts of 

 the Medusse, not only to the regions mentioned by Prof. Had- 

 don, but to the under surface of the disk, and occasionally 

 externally. They appear to adhere to the Medusae by the 

 sucker-like action of the mouth, which is widely open, though 

 the tentacles are also closely applied to the surface. 



The free-swimming larval forms are thus at a subsequent 



* Proc. Roy. Dubl. Soc. 1887, p. 473, pi. xi. 



t Physiol., Anat., & Pathol. Observations, p. 656, pi. v. figs. 21 and 22 

 (1848;. 



