ii6 THE CESTOIDEA 



ordinary sense of the word. These are deep hemispherical cups or 

 excavations at the side of the scolex, without projecting lips. They 

 are not mobile, and their muscles are delimited internally. They 

 are characteristic of the Tetracotylea (Taeniidae). 



BRANCH A. DIBOTHRIDIATA. 



Cestoidea Merozoa, in which the scolex is provided with only two of 

 these organs or "bothria," situated respectively on the dorsal and ventral 

 aspect. The uterus retains its communication with the exterior. 



ORDER 1. Pseudophyllidea, v. Ben. (Dibothridae, Dies. ; 

 Dicestoda, Perr.). 



The scolex is usually unarmed, though hooklets occur in some genera. 

 The common copulatory pore is usually on the ventral surface, though in 

 a few forms it may move to the margin of the proglottid. The uterine 

 pore is ventral. 



FAMILY 1. BOTHRIOCEPHALIDAE. Bothria more or less definite slit- 

 like furrows ; proglottids generally distinct, and drop off in groups. 

 Bothriocephalus, Hud. ; B. latus, Bremser, in the intestine of man, in 

 Russia, Switzerland, Southern France, North America. The embryos, 

 enclosed in a ciliated embryophore, swim freely in water. Pike and other 

 fresh-water fish are the intermediate hosts, but possibly they become 

 infected by devouring invertebrates containing the larvae. B. cordatus, 

 Lkt., in dog, Greenland. B. tetrapterus, v. Sieb., in Phoca. B. (Diplogono- 

 porus, Lonnb.) balaenopterae, Lonnb., with two copulatory pores in each 

 proglottid. B. (Krabbea, R. BL) grandis, Bl., Japan. B. (Anchistro- 

 cephalus, Montic.) microcephalus, Rud., in Orthagoriscus mola. Amphi- 

 tretus, R. Bl. B. (Diphyllobothrium, Cobb.) stemmacephalum, Cobb., in 

 Porpoise. Amphicotyle, Dies., with an accessory sucker to each bothrium. 

 Bothriotaenia, Raillet ; they occur mostly in fish. B. infundibuliformis, 

 Rud., in the salmon (Fig. III. 2), (see 38). B. rugdsa, Rud., lives in Gadus, 

 spp. ( = "Abothrium gadi" of van Beneden). Disymphytobothrium, Dies., 

 with peculiarly modified head, in North American sturgeon. Schisto- 

 cephalus, Crepl. (see 17). S. solidus, Crepl., in aquatic birds; the young 

 form lives in the body cavity of Gasterosteus, in which it develops so far 

 as to become segmented ; the genital organs have already appeared. 

 Ligula, Block, body unsegmented externally ; final host is some aquatic 

 bird ; the intermediate host a Cyprinoid or other fish, in the coelom of 

 which the worm attains considerable development (see 8). L. mono- 

 gramma, Crepl., a single series of genitals. L. digramma, Crepl., two 

 alternating series. FAMILY 2. SOLENOPHORIDAE. The lips of each 

 bothrium meet to form a sucking tube, usually retaining a pore at each 

 end ; genital pores ventral. Solenophorus, Crepl. (Bothridium, Blv.), (see 

 7) ; S. megalocephalus, Crepl., intestine of boa and python (Fig. III. 3). 

 Duthiersia, Perr. ; D. expansa, Perr., intestine of Varanus (Fig. III. 6) ; 

 Diplocotyle, Kr. ; D. obrikii, Kr., in Salmo carpio ; Ptychobothrium, Lonn- 

 berg ; P. belones, Lonnb. FAMILY 3. BOTHRIOMONIDAE. The two bothria 

 are replaced by a terminal, unpaired cup, which has arisen either by 



