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PACIFIC SCIENCE, VoL XX, July 1966 
TABLE 2 
Comparison of S. istihlenni with Two Other Species of Spirocamallanus 
FEATURE 
S . istihlenni 
S. spiralis 
S. pereirai 
Posterior ovary 
present 
absent 
absent 
Female: male body length ratio 
1.44:1 
1:3 
1.4:1 
Caudal papillae (male) 
9 pair 
7-9 or more 
9 pair 
No. buccal capsule spirals 
13-14 
12 
14 
Right spicule, length 
0.27 mm 
0.15 mm 
0.21 mm 
Left spicule, length 
0.18 mm 
0.1 ± mm 
0.21 
Length ratio of spicules 
3:2 
1.5:1 
2:1 
spicules are equal or unequal in length. Using 
these characteristics, Ali has created four sub- 
genera: Aspiculus, Monospiculus, Isospiculus, 
and Procdmallanus . One objection to using this 
basis of classification is that a male worm must 
be found before the female can be specifically 
identified. Also, Olsen (1952) has raised some 
doubt as to the existence of males with only 
one spicule. Yeh (I960) has dealt with the 
problem of varieties of buccal capsule linings 
by using them as bases for a "reconstruction of 
the genus Camallanus.” He created two new 
subfamilies : Camallaninae and Procamallaninae. 
The latter consists of two genera: Pro camalla- 
nus (Baylis, 1923) with a smooth buccal capsule 
lining, and Spirocamallanus Olsen, 1952, with 
spiral thickenings. I am inclined to agree with 
Yeh. 
Spirocamallanus istihlenni appears to be most 
similar to S. pereirai (Annereaux, 1946) and 
S. spiralis (Baylis, 1923). Some comparative 
features are listed in Table 2. 
In the light of the descriptions presented in 
this paper the diagnostic characteristics of the 
family Camallanidae and of the genus Spiroca- 
mallanus should include the statement that the 
posterior horn of the uterus is usually blind, 
but that a second, posterior, reduced ovary may 
be present. 
REFERENCES 
Ali, S. M. I960. On two new species of 
Pro camallanus Baylis, 1923 from India, with 
a key to the species. J. Helminthol. 34 (y 2 ) : 
129-138, 10 figs. 
Annereaux, R. F. 1946. A new nematode, 
Procamallanus pereirai, with a key to the 
genus. Trans. Am. Microscop. Soc. 65 (4) : 
299-303, 1 pk 
Baylis, H. A. 1923^. Report on a collection of 
parasitic nematodes, mainly from Egypt, Part 
III. Camallanidae, etc. Parasitology 15 (1): 
24-38, 8 figs. 
1923^. Note on Procamallanus spiralis 
Baylis, 1923 (Nematoda). Parasitology 15 
(2): 137— 138, 1 fig. 
Olsen, Leland S. 1952. Some nematodes para- 
sitic in marine fishes. Inst. Mar. Sci. (Univ. 
of Texas) 2 (2):174— 215, 5 pis. 
Yeh, Liang-Sheng. I960. On a reconstruction 
of the genus Camallanus Railliet and Henry, 
1915. J. Helminthol. 34 (l/ 2 ) : 117-124, key 
with figs. 
