ACT1NIARIA 



not as perfect as desirable. It, however, seems to me that the species is distinctly separated from the former 

 species. In its organisation it moreover recalls Haliactis arctica (p. 129), but as I have not observed any acontia 

 here, it is no more to be referred to this latter genus. 



Genus Peach ia Gosse. 



Diagnosis: Halcampoididae with a well-developed, rounded, aboral body-end, physa, perforated 

 by very numerous apertures (in twelve longitudinal rows H add on). Column more or less cylindrical, often 

 of considerable length, smooth, without " Halcampa-papillae" , indistinctly divided in regions, without spiro- 

 cysts and sphincter. Tentacles 12, not hemispherically swollen in the apices, the inner (endocoel-tentacles) 

 shorter than the outer (exocoel-tentacles) . A single, very deep and well differentiated siphonoglyphe with 

 well-developed aboral prolongation. Oral end of the siphonoglyphe drawn out in a more or less lobated 

 socalled conchula. Pairs of mesenteries 10 (6+4 lateral and ventro-lateral pairs). Only the mesenteries of 

 the first cycle perfect, fertile with filaments and with strong pennons passing into the parietal muscles with- 

 out distinct outline. Mesenteries of the second cycle with well-developed, almost pennon-like, muscle-bundles 

 in the endocoels. 



This genus is evidently most nearly related to Eloaclis and Haloclava. Synonymous with Peachia 

 is the genus Siphonactinia of Danielssen and Koren, as before pointed out by several authors. In con- 

 formity with H addon (1887, p. 475) I also think that Peachia and Bicidium are synonymous. This 

 latter genus, living parasitically on medusae, is only distinguished from Peachia by the mesenteries of the 

 second order not being developed. These mesenteries seem to originate very late in Peachia. I have namely 

 found a specimen of Peachia in the clay, the mesenteries of the second order of which were not developed 

 (compare below under Peachia hastata). This case seems to be prevailing in Eloactis. A specimen of E. mazelii 

 from a depth of 40 50 fms., taken in the Hjalte fiord Norway, shows very weak mesenteries of the second 

 cycle in only a single exocoel (compare E. mazelii textfig. 142). Furthermore it ought to be remembered 

 that reproductive organs are never found in the genus Bicidium, which is probably nothing but a larva- 

 stadium of Peachia. The conchula, not always observed in Bicidium, also seems to appear very late, and 

 probably alters its form while developing. Under such circumstances it is only with a certain reservation 

 that the form of the conchula may be used as a species-character in Peachia. 



Me. Murrich (1893, p. 145) states that Peachia koreni has only 8 tentacles. It is, however, probable 

 that the animal was a larval form with undeveloped reproductive organs, as also supposed by Me. Murrich. 



Peachia parasitica (I,. Agas.) Verr. 

 Bicidium parasiticum n. sp. Agassiz 1861, p. 24, 1865, p. 15. Verrill 1864, p. 31, PI. I, figs. 14, 15. Me. 



Murrich 1913, p. 969. Hargitt 1914, p. 239, fig. 2. 

 Philomedusa parasitica (Agass.) Andres 1883, p. 324. 



Peachia parasitica Verrill 1866, p. 338, 343, 1874, p. 739. Carlgren 1906, p. 83, figs. 7 a, b (a more com- 

 plete list of the literature is given in the latter work). 



The Ingolf-Expedilion. V. 9. '3 



