Ophichthid Eels — GosLiNE 
303 
vertebra (Fig. 9a) . At about the sixth vertebra 
the centra develop, ventrally, broad lateral 
flanges that continue to the anus (Figs. 
9b, c). These are replaced in the caudal verte- 
brae by strong transverse processes above the 
haemal arches (Fig. 9^). Neural spines are 
undeveloped except often as small backward 
projections from a few anterior vertebrae. 
Epineurals and epipleurals are developed in 
each anterior segment starting from the an- 
terior part of the column or basioccipital 
(Fig. 9a-d). Pleural ribs are present along 
most of the column and may be distinctly 
laminate (Fig. 9b, c). Epipleurals, epineurals, 
and pleural ribs extend outward and backward 
for most of the length of the fish. However, in 
the tail region these structures are replaced 
by a series of intermuscular bones, four to 
each vertebra, extending outward and for- 
ward (Fig. 10^). Muraenichthys lacks such 
intermuscular bones. Otherwise, the vertebral 
column in the species studied appears to be 
rather uniform. 
Fig. 9. Myrichthys maculosus. a. First three vertebrae 
from right. Epineurals and epipleurals are omitted from 
first two. ce, Centrum; el, epipleural; en, epineural; 
nr, neural arch, b. Vertebrae 4-6; c, vertebra 26; d, two 
anterior caudal vertebrae from below, el, Epipleural; 
fl, lateral flange of centrum; ha, haemal arch; pi, 
pleural rib; tp, transverse process of centrum. 
The total numbers of vertebrae for several 
ophichthids are shown in Table 1. Lateral-line 
pore counts for the body were also made 
(Table 1) in the hope that these might prove 
indicators of vertebral number. In a general 
way, such is the case. The discrepancies be- 
tween pore counts for the body and the num- 
ber of vertebrae is probably due, at least in 
part, to the fact that lateral line pores stop 
short of the tip of the tail, notably so in 
Brachysomophis. For example, in Cirrhimuraena 
macgregori, with a vertebral count of 181 and 
with 172 pores, the last pore is over the 171st 
vertebra. 
TABLE 1 
Vertebral Numbers and Pore Counts in Certain 
Ophichthids 
SPECIES 
NUMBER 
OF 
VERTEBRAE 
PORES IN 
LATERAL 
LINE 
Caecula platyrhyncha 
120 
120 
Brachysomophis henshawi 
130 
111 
Muraenichthys cookei 
130 
122 
Caecula flavicauda 
153 
153 
Leiuranus semicinctus 
168 
158 
Machaerenchelys phoenixensis. . . 
169 
163 
Phyllophichthus xenodontus 
170 
160 
Myrichthys maculosus 
178 
162 
Cirrhimuraena macgregori 
181 
172 
Callechelys lute us 
213 
208 
TAIL. In the past Muraenichthys has been 
placed in a different family from the other 
genera studied here. The sole reason for this 
is that Muraenichthys has a rudimentary fin 
around the tip of the tail, whereas the others 
have the tail protruding as a fleshy point. 
Osteologically, the difference between the 
tails of Muraenichthys (Fig. 10^) and Cirrhi- 
muraena (Fig. 10b) is less than that between 
those of Cirrhimuraena and Caecula platy- 
rhyncha. Rudimentary rays are present around 
the tails of both Muraenichthys and Cirrhi- 
muraena', they are merely embedded in flesh 
in Cirrhimuraena (as also in Myrichthys). In 
Caecula platyrhyncha, on the other hand, there 
are no rudimentary rays either around the tip 
of the tail or elsewhere. It is obvious from 
this discussion and more obvious from 
Figure 10 that a separate family cannot be 
maintained for Muraenichthys on the basis of 
tail structure. 
