KONGL. SV. VIST. AKADEMIENS 1IANDL1NGAR. BAND. 22. N:0 7. 45 



Thaumopn pellucida, It. v. YYlLLEMOES-SUlllM. 1874. «On a new genus of Amphi- 



pod Crustaceans'). i'hil. 

 Trans. Roy. Soc. Loud. 

 Vol. 163, p. 629 and 637, 

 pi. 49 and 50. 

 » » » J. S. Kingsley. 1884. The Standard Natural Hi- 



story. Vol.2, p. 74, tig. 99. 



Thaumatops » » G. Bovallius. 1880'. "Remarks on the genus Cy- 



steosonia or Thaumatops». 

 Bih. t. K. Sv. Vet. Ak. 

 Handl. Bd. 11. N:o 9, 

 p. 8. 

 » » » » 1887. "Systematical list of the Ara- 



phipoda Hyperiidea». Bih. 

 t. K. Sv. Vet. Ak. Handl. 

 Bd. 11. N:o 16, p. 14. 



Stebbing describes in an exhaustive manner two of the eight specimens collected 

 during the Challenger-Expedition, a male and a female; of the remaining six he points 

 out two as possibly distinct species viz: »Cystisoma, specimen F», which, if established 

 as a species by itself, he would call C. Parkinsoni, and "specimen Cr», which even- 

 tually ought to be named C. Fabricii. The former comes very near to Thaumatops 

 longipes, the latter resembles Thaumatops Loveni in the shape of the metacarpus 

 of the last pair of perasopoda, in other respects it seems to be closer connected with 

 Thaumatops spinosa. The tabular view below (p. 58) will show the measurements of 

 the hitherto known specimens, as far as I have been able to pick them up from de- 

 scriptions and drawings. These measurements will prove, I suppose, that there is closer 

 relationship between Thaumatops spinosa and Th. longipes than between Thauma- 

 tops Loveni and the two mentioned species. 



Here follows description only of Guerin-Meneville's specimen extracted from his 

 diagnosis and drawing. 



For a full account of the species I refer to the above quoted work of Stebbing. 



The head is broader and deeper than the perseon, obtusely egg-shaped, almost 

 as long, the first five pergonal segments together, measuring 25 mm. in length. From 

 the bases of the antennas runs on each side a row of 13 small teeth or spines; on the 

 under side of the head there is another row of small spines on each side. 



The first pair of antennae are three-jointed, the last joint the longest; they are 

 shorter than the head, 15 mm. long. 



The segments of the per won are high, inflated, the first and second are coalesced, 

 longer than the third segment. The fourth, fifth and sixth segments are equal in length, 

 the seventh longer, but shorter than the coalesced first and second, and shorter than the 

 first pleonal segment. They show all a sharp median keel along the dorsal side, with two 

 spine-like prominences on each segment, except the seventh which has three. 



The epimerals are coalesced with the lateral parts of the corresponding segments. 



Stout branchial sacks are attached to the fourth to sixth pairs of pera?opoda. 



