en =Y PROCEEDINGS OF THE NATIONAL MUSEUM. _ 91 
ACANTHOCEPHALA. 
Echinorhynchus rectus sp. nov. 
(Pl. tv, Figs. 13-17.) 
Two specimens of Echinorhyncius, ¢ and ?, were found among some 
fragments of Tenia collected by Mr. P.S. Jouy, at Guaymas, Mexico, 
February, 1891. The specimens were obtained from the intestines of 
Larus (Chroicocephalus) sp. 
The body is smooth, fusiform, with its greatest diameter near the . 
_ anterior end whence it tapers very gradually in both directions; probos- 
cis nearly cylindrical, implanted obliquely or at right-angles, armed 
with about twenty-four spiral series of hooks, about ten visible on one 
side in a single spiral, those on basal half straighter and more slender 
_ than those on distal half, base of proboscis for a short distance without 
hooks; sheath slender, a little longer than the proboscis; lemnisci 
slender, a little longer than the sheath. 
Male, length 8.5 millimeters ; testes two, oval, approximate, median ; 
prostatic glands represented by a broad tubular organ into which duets 
_ from the testes empty and which continues posteriorly in a large ejacu- 
latory bulb, the genitalia ending posteriorly in an eversible copulatory 
bursa. 
Female, length 9 millimeters, immature, no ova. 
Following are the dimensions of the male: 
Millimeters. 
ILRTTRIHT noant a qKeectlHneocidgs cep COCO nC nae AASEnn pppS cee aee 8. 80 
ATTLORIOLUANI CUR s velo a6 acne cic ee aceite Sale ot neds sneer nee 45 
Greaves, GIaME tls = 55s ert.ve cesta o eeice nie cee ee 80 
IP OSbELIOL GLAM OLOT ae seals See a Skee eS oe et em EN ete Sa 45 
Length of proboscis, (estimated). ...--...---...---0-+----- 1. 80 
Diameter of proboscis, anterior’. <2 .s,cac-.505o 2201. 2 fei: se .20 
PENStel Ot PlOROSEIS;: DASOs x. 2ue. tose anes ca Va ee ooee Sch 22 
LU(STEWE LO MCEy lS] YE a Cos te Pee are to ea te 1.80 
Hen arh Of OMMis@liecu., 6 saraserc oe acteeoe bc = conte eee aha 2.00 
Diam Cher OlLOMINMISCH hc clas he at Sse cece estonia oe See Biase 10 
Meng bivOriOookswrenecs tate cakes Ge erie cee eae ete . 09 
- en Sun OMbesbises cet Oe sistas aes earns eater eee c anteas . 60 
LOAM OMMUES HIS .1te te oee h ieee aes Lease eke ah. Pe geet eee ae 
The length of the proboscis was pained 1.4 millimeters was the 
length of the extended portion and 0.4 riiibh toe the length of the 
part still invaginated at the apex.. In the female the length of the 
proboscis was 1.5 millimeters with 0.4 millimeter of apex invaginated ; 
_ length of sheath, 2.2 millimeters; diameter of sheath, 0.3 millimeter at its 
widest part, near anterior, and 0.12 millimeter at its posterior end. 
Several nucleated cells were observed in the bursa of the male; these 
were 0.04 millimeter in diameter and each contained a conspicuous 
nucleus 0.01 millimeter in diameter. 
These specimens possess several points of agreement with Z. transver- 
sus Rudolphi. . 
e According to Dujardin the male of EL. transversus has only one globu- 
lar testis, while the testes of E. rectus are two in number. 
