No. 1. —A RARE THALASSINID AND ITS LARVA. 1 
BY MILLETT T. THOMPSON. 
In the summer of 1901 while working at the Woods Hole station 
of the United States fish commission on research that required daily 
examination of the plankton, my attention was attracted by a Macru- 
ran zoea which occurred at intervals throughout the latter part of 
August. A sufficient number of specimens was procured to permit 
of rearing the earlier adolescent forms. The chelicipeds of these 
stages resembled in shape those of Crangon, Pontophilus, and 
other genera of the Crangonidae , but the structure of the zoea and 
mysis stages forbade reference of the larvae to any Caridian. They 
were, therefore, tentatively assigned to the Thalassinid, Naushonia 
crangonoides , which alone of New England Macrura, outside of the 
Crangonidae , has chelicipeds of the form characteristic of that 
family. The correctness of this supposition was attested beyond 
doubt by comparison with the type specimen of Naushonia. Indeed, 
the structural resemblances tvere much closer than is frequently the 
case when adolescent and adult Decapods of the same species are 
compared. 
So far as known, only two specimens of Naushonia have been 
collected, both of which I have had opportunity to examine. The 
first specimen, a male, on which Dr. J. S. Kingsley founded the 
genus and species, was taken by Dr. II. C. Bumpus in sand from 
one of the small channels on Naushon island near Woods Hole, in 
1893. The other specimen, a female, was collected by Mr. G. M. 
Gray in July, 1899, at Ram island, a small islet in Woods Hole har¬ 
bor. Mr. Gray informs me that he dug this shrimp in sand at a 
’depth of about ten inches, the burrow having a peculiar funnel- 
shaped mouth. When collected it was carrying immature eggs on 
the abdominal appendages, but in captivity soon devoured these. 
The two specimens agree in all essentials and the following descrip¬ 
tion applies to both except when otherwise noted, although it and 
the accompanying figures were prepared mainly from the type 
specimen. 
1 From the Anatomical laboratory, Brown university, and the laboratory of 
the U. S. fish commission at Woods Hole, Mass. 
