REPORT ON THE ACTINIARIA. 21 



former possesses but one stomidium, the latter apparently must be provided each with 

 two or three, — an inference confirmed by dissection. Since it is the rule amongst 

 Actinia? that the development of tentacles precedes that of mesenteries, we can also 

 infer in this instance from the plentiful development of stomidia, an imminent addition 

 to the mesenteries. 



Genus Aulorchis, n. gen. 



Liponemidae, whose generative organs are modified into a tube perforating the oral 

 lip ; gonidial grooves on both sides drawn out into a long ear-like cone. 



Aulorchis paradoxa* sp. n. (PI. I. figs. 9, 10 ; PI. III. figs. 2-6 ; PI. IV. figs. 1-6). 



Stomidia arranged in two alternating rows, approximately sixty in number. 



Habitat— Station 299, December 14, 1875; lat. 33° 31' S., long. 74° 43' W.; 

 depth, 2160 fathoms. One specimen. 



Dimensions. — Height, 4 cm. ; greatest breadth (measured about half-way up the 

 animal), 3 cm. 



Among the accessory Challenger Actinias occurs this form, of great interest as 

 enlarging by a new genus and new species the group of forms devoid of tentacles. 

 Unluckily, I have had but the one solitary specimen for study, and even this was badly 

 preserved, and had apparently suffered much from the dredge. It was exceedingly 

 contracted ; oral and pedal discs were externally unrecognisable, since both ends of the 

 body-wall were closely drawn together. As a natural result of this condition, I have 

 not been able to clear up many important points of the organisation so well as I could 

 have wished. For investigation, I divided the specimen longitudinally, and dissected a 

 sextant with scalpel and scissors, arriving at the following results. 



The strongly contracted, and therefore small, pedal disc exhibits indistinct radial 

 brownish wrinkles and furrows, and is sharply marked off from the body-wall, the 

 surface of which is smooth. The latter is of a whitish tint, and of inconsiderable thick- 

 ness, only here and there becoming more powerful, but never forming hooks or papillae. 

 Its consistence is less firm than that of cartilage, but considerably more so than that of 

 Medusan mesogloea. The tissue is of a fibrous nature, composed of very fine fibrils, 

 which are generally interlacing and reticulate. At many points, however, they are 

 thicker and bound together in more parallel series, so that cords and lamellae are 

 formed, which, though staining brilliantly with carmine, are not sharply differentiated 

 from their surroundings. These lamellae are ranged parallel to the two surfaces, and 

 run constantly closer to one another till a firmly united mass of fibres is formed just 

 below the epithelium. At other points, however, the fibres are more loosely plaited, so 

 that spaces remain between them, which are filled up by homogeneous mesoglcea. 

 In some places I detected hollow spaces in the tissue, which were devoid of an epithelial 



