50 PROFESSOR OSKAR CARLGREN ON THE GENUS PORPONIA 



Scotia Expedition has proved, however, that the arrangement of the mesenteries, as 

 also indeed a number of other characters, indicates a close relationship between 

 Halcurias (Endoccelactis) and Porponia, though each genus has its own distinctive 

 characteristics. They must of necessity be referred to the same family, though this 

 cannot be the Antheomorphidse set up by Hertwig, with its genera Antheomorphe and 

 llyanthopsis. As the following description will show, I have no hesitation in retaining 

 the family set up by me, Endoccelactidse, for Halcurias and Porponia. 



After describing in detail the Porponia species of the Scotia Expedition, I shall 

 discuss the mutual relationship of Halcurias and Porponia, and the position of the 

 family Endoccelactidge in the classification. At the same time I shall take the 

 opportunity to discuss the genera Antheomorphe and llyanthopsis, as also the family 

 Antheomorphidse. 



I. The Structure of Porponia Antarctica, n. sr 



Place of discovery.— Off Coats Land, 71° 22' S., 16° 34' W., 1410 fathoms, 16th 

 March 1904. 17 specimens. 



Dimensions of the largest specimens. — Length 6-8 cm., breadth of the foot 3-4 

 cm., breadth of the disc 8-9 cm., length of the inner tentacles 3-7 cm. 



External appearance. — The fresh colour is creamy white, tinged, especially on the 

 tentacles, with pale lavender. The base is expanded and often attached to a round 

 stone, which it more or less encloses ; it is arranged in coarse, irregular folds, and 

 secretes a fairly extensive cuticle. 



The body-wall is more or less beaker-shaped, arising from the less or greater 

 contraction of the individuals. The distal part of the animal is thus wider than the 

 proximal, and that often to a fairly considerable extent. The thick body-wall is 

 provided with irregular longitudinal and transverse furrows, by means of which it is 

 divided into irregular areas, as a rule very prominent, since the thin ectoderm has 

 fallen off from almost all the specimens. The distal, uneven edge of the body-wall is 

 not marked off by any definite groove or line, but passes irregularly into the bases of 

 the tentacles. In large specimens the tentacles are typically 68 * in number, yet this 

 may be exceeded, as the arrangement of the tentacles and even the grouping of the 

 mesenteries may be somewhat irregular in one quadrant (or several ?), resulting in a 

 somewhat greater development of tentacles here than in the other quadrants. The 

 tentacles have the appearance characteristic for Porponia ; on the outer side they are 

 greatly thickened and like cartilage ; towards the oral disc, on the inner side, they are 

 thin and resemble ordinary tentacles. Owing to the mesogloea being greatly thickened 

 on the outer sides of the tentacles, it looks as if the tentacles here were provided with 

 bridge-like outshoots from the body-wall. Further, the tentacles are conical, curved 



* The normal number of tentacles seems to be developed in the species at a comparatively early stage, as specimens 

 of only half the size of the largest in the collection have already the typical number of tentacles. A small specimen, 

 on the other hand, had considerably fewer tentacles ; but as it was much damaged, I have not tried to ascertain exactly 

 the number of tentacles or their arrangement. 



