The Origin and Development of the Spermatophoric 
Mass of a Nephropsid Lobster, Enoplometopus 
occidentalis (Randall)^ 
Donald C. Matthews^ 
INTRODUCTION 
The purpose of this paper on the origin 
and development of the spermatophoric mass 
of Enoplometopus occidentalis (Randall) is three- 
fold: (1) to increase our knowledge of the 
biology of this little-known species, (2) to 
show evidence in support of external fertiliza- 
tion, and (3) to extend the list of mechanically 
sperm-liberating families in Hawaii to include 
theNephropsidae(Homaridae auct., Nephrop- 
sidae fide Holthuis, 1946). 
With the possible exception of the Cape 
crayfish (Jasus lalandii, von Bonde, 1936), all 
recorded observations indicate that the pali- 
nurids, the astacids, and the homarids produce 
continuous, highly convoluted spermato- 
phoric tubes embedded in putty-like matrices 
(Panulirus interruptus — Allen, 1916; Fasten, 
1917; Wilson, 1949; P. argus—Cmwfosd and 
De Smidt, 1923; P. penicillatus— Msitthews, 
1951; Potamohius trowhridgii—AndtQ^s, 1931; 
Homarus americanus—^tlQmcV, 1895). 
Although the process has not been observed 
in every case, female pereiopodal gouging of 
these spermatophores during oviposition 
probably allows the liberation of their sper- 
matozoa and the subsequent external fertil- 
ization. 
Among macruran spermatophores studied, 
mechanical liberation of sperm reaches its 
highest development in the scyllarid Parri- 
bacus antarcticus (Lund). The spermatophoric 
mass resembles that of the palinurids, the 
astacids, and the homarids, but certain of the 
pereiopods are provided with special structures 
^ Contribution number 43, Hawaii Marine Lab- 
oratory. Manuscript received May 28, 1953. 
2 Department of Zoology and Entomology, Uni- 
versity of Hawaii, Honolulu, Hawaii. ^ 
for the mechanical liberation of the sperma- 
tozoa (Andrews, 1912; Matthews, 1953). Here, 
likewise, fertilization is probably external. 
Although once obtainable from Honolulu 
markets {vide Rathbun, 1906: 900), E. occi- 
dentalis is now seldom seen here except at the 
Honolulu Aquarium, although it is occasion- 
ally taken on the reefs and at depths of a few 
fathoms {vide Edmondson, 1946: 257). Yet 
large numbers of Enoplometopus postlarvae 
found in the stomachs of the yellowfin tuna 
Neothunnus macropterus (Reintjes, unpubl. ms.) 
attest its prevalence in deeper water. Although 
only males were obtainable for dissection, a 
single female in the collection of the Bernice 
P. Bishop Museum was available for observa- 
tion. This specimen was devoid of sperma- 
tophoric mass. The spermatophoric mass of 
E. occidentalis in so far as can be ascertained 
has not been investigated. 
The writer wishes to thank Mr. Spencer 
Tinker, director of the Honolulu Aquarium, 
who furnished the living specimens. 
METHODS AND TECHNIQUES 
Mature male specimens of E. occidentalism 
obtained from the Honolulu Aquarium in 
November, 1952, were used in this study. 
The reproductive organs were removed, fixed 
in either Bouin’s or Zenker’s fluid, dehy- 
drated and cleared in dioxane, embedded in 
Tissuemat (54-56°C.), and sectioned at 10 
microns. The mounted sections were stained 
with standard alumhaematoxylin and coun- 
terstained with eosin. 
Certain vasa efferentia were placed in 0.1 
N KOH. Others were dissected, the sperma- 
tophoric mass smeared on small glass plates, 
and these immersed in sea water. 
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