328 Miscellaneous. 



vessel rests, exactly as the ambulacral vessel of the Comatulce rests 

 in the furrow of the arm-skeleton. The ambulacral pieces hitherto 

 absolutely characteristic of the class Stellerida are deficient in the 

 Hymenodisci. A few irregular calcareous trabecular uniting the 

 lateral pieces of the arm-skeleton are their sole representatives in 

 the neighbourhood of the mouth. It is to be noted that the cha- 

 raters furnished by the pedicellariae have survived the characters 

 furnished by the constitution of the ambulacral groove, which has 

 hitherto been regarded as typical ; and this is a confirmation of the 

 value which I thought ought to be attached to the pedicellariae in 

 the classification of the starfishes when I proposed to substitute the 

 indications furnished by them for those derived from the number of 

 rows of ambulacral tubes, which had been depended on by Midler 

 and Troschel. The absence of ambulacral pieces, and of calcareous 

 pieces covering the groove on the oral surface of the arms, does not 

 allow us to compare the organization of the arms of Hymenodiscus 

 except to that of the arms of the Comatulaj. The contrast between 

 the arms and the disk, and the probable absence of genital glands 

 and digestive creca from the arms, on the other hand, approximate 

 the Hymenodisci to the Ophiuri ; by the absence of ambulacra! pieces, 

 and consequently of buccal pieces, they depart from all known 

 Stellerida ; their pedicellariae, however, indicate that they constitute 

 an aberrant form of the division of the Asteriada?, in which they 

 take their place, but as a distinct family, by the side of Labidi- 

 aster, Pedicellaster, and Brisinga, which, like them, possess only 

 two rows of ambulacral tubes. Labidiaster has a much greater 

 number of arms ; Pedicellaster has only five ; the Brisingoe from 

 eleven to twelve, but quite differently constructed. These latter 

 animals, in fact, enter without any difficulty into the ordinary 

 type of starfishes, of which the Hymenodisci constitute a form 

 quite different from any thing hitherto known to us, and pre- 

 senting the most exceptional characters. — Comptes Bendus, Aug. 30, 

 1880, p. 436. 



On Gastrosaccus spinifer. By Thomas R. E. Stebbikg. 



During the present month of August I have been successful in 

 finding Gastrosaccus spinifer of both sexes at Whitby, in the sand 

 at low water. I have also had the opportunity of seeing specimens 

 and mountings of the species in Mr. Norman's very extensive col- 

 lection of Crustacea. Mr. Norman has called my attention to the 

 erroneous formation of the specific name spinifer us, which must of 

 course be written spinifer. There can, I think, be no doubt what- 

 ever that the name G. sanctus must be confined to the species de- 

 scribed by Sars under that title, as quite distinct from the present 

 G. spinifer of Goes. At the same time, one of Mr. Norman's dis- 

 sections, which agrees exactly with a subsequent one of my own, 

 seems to show decidedly that the marsupial pouch is attached to 

 the first pleopods, contrary to the criticism of Prof. G. 0. Sars, who 

 denies the attachment of the marsupium to the first pleon-segment. 

 It may be further remarked that the number of spines on the telson 

 and uropods appears to be subject to slight variations in different 

 specimens. 



Tunbridge Wells, Aug. 31, 1880. 



