HUBBS and WISNER: REVISION OF THE SAURIES 



ovary in this species (nor in the other dwarf, E las- 

 sie hthys adocetus). 



In cross section the maturing and mature 

 ovaries of both dwarfs are rather ovate in section. 

 They very nearly fill the whole coelom between the 

 much expanded body walls, particularly in Elas- 

 sichthys (Figure 8). As they ripen, the ova fill the 

 entire ovary so tightly that many of the ripe ova 

 and even some of those in developmental stages 

 are compressed into angular forms throughout the 

 ovary. Forward, the ovai-y narrows dorsoventrally 

 where the liver broadens to fill much of the coelom. 

 Gentle probing readily discloses that the ovary 

 lacks any structural connection with the coelom 

 wall (except at the genital opening), although, 

 with development, the ovary completely fills the 

 body cavity above the visceral organs and lies 

 closely appressed to the body wall, both dorsally 

 and laterally. Dislodging the ova by probing dis- 

 closes no trace of any internal septum. 



The ova in the mature ovary of Nanichthys and 

 Elassichthys appear on gi'oss examination to rep- 

 resent at least four stages of development, but a 

 major difference in size exists between the largest 

 category (readily visible in Figure 8) and the next 

 largest, as though an acceleration in growth pre- 

 cedes the extrusion of the brood. Since the ova of 

 the largest category are usually markedly irregu- 

 lar in shape (presumably due to crowding), mea- 

 surements are approximations. However, after 

 discharge the ova are probably normally spherical 

 rather than ovoid in shape, as the eggs oi^Cololabis 

 saira have been described to be (Mito 1958; 

 Mukacheva 1960). The largest egg size in the 

 Nanichthys series studied ranged in diameter 

 from 2.0 to 2.5 mm. The smaller and presumably 

 younger size groups seemed to group around 0.80, 

 0.40, and 0.10 mm. Similar size groupings ap- 

 peared to hold for Elassichthys. 



The positioning of the largest eggs in the ovaries 

 of the dwarfs seems to be quite random among the 

 smaller ones (Figure 8). These large eggs were 

 noted to be arranged generally mostly two abreast 

 (three abreast once in Elassichthys). The random 

 distribution of the large eggs within an ovary 

 otherwise filled with smaller eggs invites specula- 

 tion on how the anteriormost eggs of the largest 

 size category move past the smaller ones to become 

 extruded. 



None of the eggs of the dwarfs, even of the 

 largest and presumably soon-to-be-extruded cate- 

 gory, show any sign of bearing filaments. Their 

 surfaces, however, are sculptured with closely 



set, round, and extremely minute tubercles which 

 are colorless (in preservative) and produce, under 

 strong magnification, a finely pebbled effect. 



It has not been determined whether the single 

 ovary of the two dwarfed scomberesocids is the 

 result of the fusion of bilateral primordia oris due 

 to the failure to develop, or to the atrophy, of one 

 ovary. The presence of but one gonad in synentog- 

 nath fishes has been reported. Collette ( 1968) indi- 

 cated that in the Belonidae Strongyliira marina 

 differs from a closely related species, S. timiicu , in 

 having only the right gonad developed. Collette 

 ( 1974) reported that in the freshwater needlefish, 

 S. hubbsi, 48 males had both testes developed but 

 2 apparently lacked the left one, and of 45 females, 

 2 had a tiny left ovary but all others lacked any 

 trace of a left ovary. 



In contrast with the ovary, the testis of both 

 Nanichthys and Elassichthys . at apparent matur- 

 ity, occupies only about one-third instead of about 

 three-fourths of the height of the fleshy body (Fig- 

 ure 9). The testis agrees with the ovary, however, 

 in occupying virtually the entire ( limited ) width of 

 the coelom, forming from body wall to body wall a 

 compact and compressed organ of seemingly 

 homogeneous reproductive tissue. However, close 

 inspection and some probing with a fine dissecting 

 needle clearly discloses that the dorsally rounded 

 mass comprises both testes. As seen from the right 

 side, on removing the body wall (Figure 9), a fine, 

 somewhat wavy longitudinal line, nearer top than 

 bottom, indicates that the essentially homogene- 

 ous structure comprises the paired testes, and gen- 

 tle probing confirms the indication. The left testis 

 is definitely the larger, but both are well de- 

 veloped and are obviously functional. The two are 

 essentially co terminal along the ventral edge, but 

 the left testis definitely and sharply overtops the 

 right. Ventrally the two organs form, at about the 

 same level, symmetrical ridges on a rather broad 

 base. At front, the paired testes are clearly distinct 

 as lobes, of which the right one ends distinctly as a 

 point, at that side of the left one. Anterior to the 

 end of the right organ, the left one broadens on the 

 ventral surface and forms a pair of bilaterally 

 paired ridges, the left one of which seems to struc- 

 turally replace the lost end of the right testis. 



Mucus Pores and Canals of the Head 



Numbers and arrangement of mucus pores and 

 canals of the head vary notably among the scom- 

 beresocids (Figure 10, items 1-6). Adults of the two 



545 



