— 11 — 



circular canal. In the bottom of tlie anterior portion of the fossa there is, in my specimen, a foramen 

 — if it be not perhaps simply a defect in the bone — which opens into that canal that leads from the 

 cranial cavitv to the upper one of the two apertures called by Sagemehl, in his figures of Erythrinus, 

 the facialis foramina. The opening is so inconspicuous that I should not have noticed it had I not been 

 led to look for it, because of the canal here fonnd in Elops. There are also in my specimen, two per- 

 forations of the bony partition that separates the temporal fossa from the dilatator fossa, one of the 

 perforations undoubtedly giving passage to the ramus oticus, and the other probably to a venous 

 vessel similar to the one that, in Scorpaena, accompanies the oticus in its backward course, as will 

 be later described. These several foramina are not described by Sagemehl, and furthermore that 

 author's descriptions of the foramina that perforate the lateral wall of the proötic are certainly not 

 wholly correct. The so-called jugular foramen is found, as shown, opening directly into the labyrinth 

 recess, but this opening in the prepared skull must certainly be closed, in the recent state, by mem- 

 brane, and hence can not transmit the jugular vein. In the anterior edge of this foramen a small canal 

 begins in the wall of the proötic and, running forward, traverses the base of that flange that forms 

 the anterior wall of the labyrinth recess and so enters a recess of the cranial cavity into which the 

 so-called facialis and trigeminus foramina open. This cranial recess probably lodges, as in Cottus, 

 and as will be fully described when describing that fish, the profundus, communis and lateralis ganglia 

 of the trigemino-facialis complex, the trigeminus ganglion probably having an extracranial position. 

 If this be so, the jugular vein, as in Cottus, does not enter the recess, but lies along the outer surface 

 of the skull immediately beneath the extracranial trigeminus ganglion. One of the two foramina 

 marked ,,fa" in Sagemehl's figures must then transmit the truncus hyoideo-mandibularis facialis, 

 the other one, said by him to transmit a vein, probably transmitting the encephalic brauch of the 

 jugular vein. What the little canal in the proötic that I have just above described transmits, I can 

 not teil, and it may perhaps be an artifact. 



In Catostomus teres and Moxostoma sucetta, of the Cyprinidae, the axis of the temporal fossa 

 is said by Sagemehl ('91, pp. 550 — 553) to lie in a frontal (transverse?) position and the fossa is said 

 to open on the lateral instead of on the posterior surface of the skull. The anterior portion only of the 

 fossa is roofed, the roof there being formed by the mesial edge of the dermal jiortion of the pterotic, 

 the lateral edge of the epiotic (exoccipitale), and, between those two bones, by a portion of the parietal. 

 In the genus Sclerognathus, the roofing portions of these several bones are said to have almost dis- 

 appeared, and in the genus Diplophysa to have entirely disappeared; the fossa of this latter fish thus 

 becoming a simple pit or groove on the dorsal surface of the skull, the homologue, apparentlv, of the 

 groove in Scorpaena, and not of that in Scomber. The extrascapular and suprascapular bones are not 

 here considered by Sagemehl as roofing bones of the groove, but they are nevertheless found in all 

 the Cyprinidae (1. c, p. 507), the extrascapular as a small scale-like bone at the hind edge of the 

 pterotic, and the suprascapular as a long, lance-like bone that lies along the hind edges of the pterotic 

 and epiotic and there roofs the posterior entrance of the temporal groove. In certain others of the 

 Cyprinidae, the temporal fossa is said by Sagemehl to be reduced to a simple and narrow canal which 

 opens on the posterior surface of the skull between the pterotic and epiotic. In the genera Nemachilus, 

 Misgurnus, Cobitis and Acanthophthalmus even this narrow canal is said to become almost entirely 

 obliterated. 



A temporal fossa, similar to that of Sclerognathus, is said by Sagemehl to be found in very 

 many of the Physostomi and in nearly all the Acanthopterygii and Anacanthini. This I am inclined 



