MALE AND THE STRUCTURE OF THAUMOPS PELLUCIDA. 
637 
Appendix. 
On the Male and the Structure of Thaumops pellucida. 
Received October 24, — Read December 11, 1873. 
Since my paper on the large Hyperid was read at the Royal Society, three males 
of Thaumops have been caught by us. One of these, which was taken at the surface 
in the towing-net during the night, was very much spoiled ; and I dissected its oral 
apparatus in order to elucidate several points about which I remained doubtful when 
I examined the female. 
The largest of the males is 103 millims. in length, exceeding in length the large 
female by 19 millims., and showing that Thaumops attains a prodigious size. It was 
caught by the trawl in lat 5° 48' N., long. 14° 20' W. Another very well-preserved 
male is younger, only 46 millims. long, but shows the genital organs better. These 
males differ from the females by the absence of the genital openings at the base of the 
first segment and of the breeding lamellae. The two elongate testes begin just behind 
the caecum of the stomach, and their vasa deferentia run down to the last segment of 
the pereion, where they terminate by two simple openings between the last pair of 
pereiopods. 
There is not a trace of a second pair of antennae, either in the male or in the female. 
In the former, however, the first pair of antennae, the five pairs of ambulatory pereiopods, 
and the caudal appendages are distinguished by the want of the glandular apparatus. 
In the female these glands cause an enlargement at the top of each of the appendages 
in question, and this enlargement is of course also wanting in the male. 
The anterior antennEe have, in the large male, a length of 18 millims., and consist of 
two joints, the first of which is very short. The oral apparatus presents the same 
papillar shape which I figured in the female ; but the mandibles, which at first I 
thought were entirely wanting, have now been found. They are very much like those of 
Phronima , only shorter and not so elongate as in that animal ; the palpus, which is 
present in the mandibles of the male Typliidce , could not be detected in Thaumops. 
The first maxillae are also very small, and differ by their shortness from those of 
Phronima, but otherwise show the same characters. The second maxillae could not 
be found with certainty ; they are either wanting or represented by an organ which I 
thought was the labium (Plate L. fig. 6, lab). This organ arises from the second 
joint of a very peculiar appendage, which I have interpreted in my first paper as maxillae 
(Plate L. fig. 6, ma). I am now satisfied, however, that these are the maxillipeds, con- 
sisting of three joints. Two of these joints are united together, the first being attached 
